1. Field of the Invention
The invention relates to an automation device having a master module, and a slave unit having a plurality of slave modules, where an interface module (IM) of the plurality of slave modules of the slave unit is connected to the master module via a bus, where each of the plurality of slave modules is parameterizable using a message transmitted to the IM by the master module, and where the message includes a data area for each of the plurality of slave modules for parameterization of each of the plurality of slave modules.
2. Description of the Related Art
An automation device is known from the Siemens catalog ST PCS 7, June 2012 edition, chapter 8. So-called “decentralized peripherals” are provided for tackling automation tasks in a decentralized manner in the field of production, process and method technology and usually comprise different slave units or peripherals that are provided with a plurality of slave modules and are each connected to a master module via an IM of the slave units and via a PROFIBUS DP. In this case, the master module is usually part of a powerful programmable logic controller that is provided with at least one CPU module and further functional modules and is intended to tackle more complex automation tasks, where the CPU module itself is able to be designed to undertake the tasks of the master module.
Actuators and/or sensors can be connected to these slave modules of a slave unit, where process peripheral input data transmitted from the sensors can be stored in the slave modules, and process peripheral output data that are transmitted to the slave modules by the master unit can be supplied to the actuators by the slave modules.
So that a slave unit formed with a plurality of slave modules can be used to tackle automation tasks, the slave modules must be parameterized. For this purpose, the master module transmits a message having a message identifier (i.e., a data record number), which indicates that the message is a parameter message, to the IM of the slave units via the bus. In addition to this message identifier, the message has data areas comprising the address of the slave unit to be addressed, the slot addresses or the slot numbers of the slave modules in the slave unit and parameters for parameterizing the slave modules. The size of these data areas of all slave modules usually must not exceed 244 bytes, which means that the number of slave modules which can be operated or used in a slave unit is restricted. For example, the situation may occur in which a data area of 50 bytes is respectively required for a first slave module and a second slave module of one manufacturer or supplier and a data area of 150 bytes is required for a slave module of another manufacturer on account of the multiplicity of parameters which can be set. This means that these three slave modules cannot be used together in a slave unit because the message length with respect to the data area of 244 bytes cannot be exceeded.